1990 WAEC SSCE Chemistry Past Questions

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1990

(a)(i) Give one laboratory use of activated charcoal(ii) A piece of phosphorus and some magnesium ribbon were burnt in two separate jars of oxygen. Water was then added to dissolve the product. State the action of litmus…

1990

Credit will be given for strict adherence to the instructions, for observations precisely recorded, and for accurate inferences. All tests, Observations, and inferences must be clearly entered in your answer book, in ink…

1990

All your burette readings (initial and final) as well as the size size of your pipette, must be recorded but no account of experimental procedure is required. All calculations must be done in your answer book. Xg of pure…

1990

(a)(i) Define oxidation in terms of electron transfer.(ii) Write balanced equations for the half reactions for the following changes in acidic solution: Mn0\(^-_4\) + Fe\(^{2+}\) > Mn\(^{2+}\) + Fe\(^{3+}\)(b)(i) Dist…

1990

(a)(i) Define the term addition polymerization(ii) What type of organic compounds undergo addition polymerization(iii) List two factors which affect the strength of polymers(b) The diagram below shows some reaction pathw…

1990

Consider the reaction represented by the equation: 2SO\(_{2(g)}\) + O\(_{2(g)}\) 2SO\(_{3(g)}\). \(\Delta\)H = 188KJ.(a) Write an expression for the equilibrium constant(b) Sketch an energy diagram for the forward react…

1990

(a)(i) List two physical properties used as criteria for purity of substances(ii) describe how you would prepare a pure, dry sample of sodium chloride crystals by a neutralization reaction, using bench reagents.(iii) Giv…

1990

Liquefied air is mainly a mixture of nitrogen and oxygen which can be separated into its components by fractional distillation (Boiling point of nitrogen is 196°C, Boiling point of oxygen is 174°C)(a) Name the fraction w…

1990

(a) Name the type of solid structure possessed by:(i) diamond;(ii) iodine;(iii) sodium chloride.(b) Give:(i) one alloy of tin:(ii) a common reducing agent which is a compound of tin.

1990

(a) Arrange the first three members of the halogen family in their increasing order of electronegativity. Give the reason for your answer.(b) State and explain what happens when chlorine reacts with starch iodide paper.

1990

Benzene contains six carbon atoms and six hydrogen atoms.(a)(i) Draw two stable structures of benzene to show how these atoms are arranged.(ii) What is the concept behind these structures?(b) Give (i) two uses of benzene…

1990

(a) Give the formula indicating the relationship between entropy, free energy and enthalpy changes of a system.(b) For each of the following, state whether entropy change is positive, negative or zero.(i) H\(_2\)O\(_{(g)…

1990

(a) Give one reason why a collision between reactants may not produce new species.(b) Explain, illustrating with appropriate equation(s), why an aqueous solution of aluminium chloride is acidic.

1990

(a) Balance the nuclear equation below and hence identify Y.\(^{238}_{94}U \to ^{234}_{92}Th + Y\)(b) In a tabular form, state two of the observations in the cathode ray experiment and the corresponding deductions.

1990

A hydrocarbon X which decolorizes bromine water but has no action on ammoniacal silver trioxonitrate (V) solution was found to have a molar mass of 58 g mol\(^{-1}\)(a) Deduce the molecular formula of X. (H = 1, C = 12)…

1990

(a) Give two reasons why carbon(IV) oxide is used for extinguishing fire(b) Explain briefly the water softening action of cation exchange resins.

1990

(a) Write the electronic configuration of an element with atomic number 15, indicating the distribution of electrons in the energy sub-levels(b) Give the formula and the colour of the complex formed between ammonia and c…

1990

The heat accompanying the reaction represented by the equation H2O (l) → H 2O(g) is described as the heat of

1990

The electronic configuration 1s22s22p63s23p6 is that of a

1990

A sample of orange juice is suspected to have been contaminated with a yellow dye. Which of the following methods can be used to detect the dye?

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1990 WAEC SSCE Chemistry Past Questions

(a)(i) Give one laboratory use of activated charcoal(ii) A piece of phosphorus and some magnesium ribbon were burnt in two separate jars of oxygen. Water was then added to dissolve the product. State the action of litmus…

Credit will be given for strict adherence to the instructions, for observations precisely recorded, and for accurate inferences. All tests, Observations, and inferences must be clearly entered in your answer book, in ink…

All your burette readings (initial and final) as well as the size size of your pipette, must be recorded but no account of experimental procedure is required. All calculations must be done in your answer book. Xg of pure…

(a)(i) Define oxidation in terms of electron transfer.(ii) Write balanced equations for the half reactions for the following changes in acidic solution: Mn0\(^-_4\) + Fe\(^{2+}\) &gt; Mn\(^{2+}\) + Fe\(^{3+}\)(b)(i) Dist…

(a)(i) Define the term addition polymerization(ii) What type of organic compounds undergo addition polymerization(iii) List two factors which affect the strength of polymers(b) The diagram below shows some reaction pathw…

Consider the reaction represented by the equation: 2SO\(_{2(g)}\) + O\(_{2(g)}\) 2SO\(_{3(g)}\). \(\Delta\)H = 188KJ.(a) Write an expression for the equilibrium constant(b) Sketch an energy diagram for the forward react…

(a)(i) List two physical properties used as criteria for purity of substances(ii) describe how you would prepare a pure, dry sample of sodium chloride crystals by a neutralization reaction, using bench reagents.(iii) Giv…

Liquefied air is mainly a mixture of nitrogen and oxygen which can be separated into its components by fractional distillation (Boiling point of nitrogen is 196°C, Boiling point of oxygen is 174°C)(a) Name the fraction w…

(a) Name the type of solid structure possessed by:(i) diamond;(ii) iodine;(iii) sodium chloride.(b) Give:(i) one alloy of tin:(ii) a common reducing agent which is a compound of tin.

(a) Arrange the first three members of the halogen family in their increasing order of electronegativity. Give the reason for your answer.(b) State and explain what happens when chlorine reacts with starch iodide paper.

Benzene contains six carbon atoms and six hydrogen atoms.(a)(i) Draw two stable structures of benzene to show how these atoms are arranged.(ii) What is the concept behind these structures?(b) Give (i) two uses of benzene…

(a) Give the formula indicating the relationship between entropy, free energy and enthalpy changes of a system.(b) For each of the following, state whether entropy change is positive, negative or zero.(i) H\(_2\)O\(_{(g)…

(a) Give one reason why a collision between reactants may not produce new species.(b) Explain, illustrating with appropriate equation(s), why an aqueous solution of aluminium chloride is acidic.

(a) Balance the nuclear equation below and hence identify Y.\(^{238}_{94}U \to ^{234}_{92}Th + Y\)(b) In a tabular form, state two of the observations in the cathode ray experiment and the corresponding deductions.

A hydrocarbon X which decolorizes bromine water but has no action on ammoniacal silver trioxonitrate (V) solution was found to have a molar mass of 58 g mol\(^{-1}\)(a) Deduce the molecular formula of X. (H = 1, C = 12)…

(a) Give two reasons why carbon(IV) oxide is used for extinguishing fire(b) Explain briefly the water softening action of cation exchange resins.

(a) Write the electronic configuration of an element with atomic number 15, indicating the distribution of electrons in the energy sub-levels(b) Give the formula and the colour of the complex formed between ammonia and c…

The heat accompanying the reaction represented by the equation H2O (l) → H 2O(g) is described as the heat of

The electronic configuration 1s22s22p63s23p6 is that of a

A sample of orange juice is suspected to have been contaminated with a yellow dye. Which of the following methods can be used to detect the dye?

(a)(i) Define oxidation in terms of electron transfer.(ii) Write balanced equations for the half reactions for the following changes in acidic solution: Mn0\(^-_4\) + Fe\(^{2+}\) > Mn\(^{2+}\) + Fe\(^{3+}\)(b)(i) Dist…